export default function HZRecorder(stream, config) {
	config = config || {};
	config.sampleBits = config.sampleBits || 16; //采样数位 8, 16
	config.sampleRate = config.sampleRate || 16000; //采样率16khz

	var context = new(window.webkitAudioContext || window.AudioContext)();
	var audioInput = context.createMediaStreamSource(stream);
	var createScript = context.createScriptProcessor || context.createJavaScriptNode;
	var recorder = createScript.apply(context, [4096, 1, 1]);

	var audioData = {
		size: 0 //录音文件长度
			,
		buffer: [] //录音缓存
			,
		inputSampleRate: context.sampleRate //输入采样率
			,
		inputSampleBits: 16 //输入采样数位 8, 16
			,
		outputSampleRate: config.sampleRate //输出采样率
			,
		oututSampleBits: config.sampleBits //输出采样数位 8, 16
			,
		input: function(data) {
			this.buffer.push(new Float32Array(data));
			this.size += data.length;
		},
		compress: function() { //合并压缩
			//合并
			var data = new Float32Array(this.size);
			var offset = 0;
			for (var i = 0; i < this.buffer.length; i++) {
				data.set(this.buffer[i], offset);
				offset += this.buffer[i].length;
			}
			//压缩
			var compression = parseInt(this.inputSampleRate / this.outputSampleRate);
			var length = data.length / compression;
			var result = new Float32Array(length);
			var index = 0,
				j = 0;
			while (index < length) {
				result[index] = data[j];
				j += compression;
				index++;
			}
			return result;
		},
		encodeWAV: function() {
			var sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate);
			var sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits);
			var bytes = this.compress();
			var dataLength = bytes.length * (sampleBits / 8);
			var buffer = new ArrayBuffer(44 + dataLength);
			var data = new DataView(buffer);

			var channelCount = 1; //单声道
			var offset = 0;

			var writeString = function(str) {
				for (var i = 0; i < str.length; i++) {
					data.setUint8(offset + i, str.charCodeAt(i));
				}
			}

			// 资源交换文件标识符 
			writeString('RIFF');
			offset += 4;
			// 下个地址开始到文件尾总字节数,即文件大小-8 
			data.setUint32(offset, 36 + dataLength, true);
			offset += 4;
			// WAV文件标志
			writeString('WAVE');
			offset += 4;
			// 波形格式标志 
			writeString('fmt ');
			offset += 4;
			// 过滤字节,一般为 0x10 = 16 
			data.setUint32(offset, 16, true);
			offset += 4;
			// 格式类别 (PCM形式采样数据) 
			data.setUint16(offset, 1, true);
			offset += 2;
			// 通道数 
			data.setUint16(offset, channelCount, true);
			offset += 2;
			// 采样率,每秒样本数,表示每个通道的播放速度 
			data.setUint32(offset, sampleRate, true);
			offset += 4;
			// 波形数据传输率 (每秒平均字节数) 单声道×每秒数据位数×每样本数据位/8 
			data.setUint32(offset, channelCount * sampleRate * (sampleBits / 8), true);
			offset += 4;
			// 快数据调整数 采样一次占用字节数 单声道×每样本的数据位数/8 
			data.setUint16(offset, channelCount * (sampleBits / 8), true);
			offset += 2;
			// 每样本数据位数 
			data.setUint16(offset, sampleBits, true);
			offset += 2;
			// 数据标识符 
			writeString('data');
			offset += 4;
			// 采样数据总数,即数据总大小-44 
			data.setUint32(offset, dataLength, true);
			offset += 4;
			// 写入采样数据 
			if (sampleBits === 8) {
				for (var i = 0; i < bytes.length; i++, offset++) {
					var s = Math.max(-1, Math.min(1, bytes[i]));
					var val = s < 0 ? s * 0x8000 : s * 0x7FFF;
					val = parseInt(255 / (65535 / (val + 32768)));
					data.setInt8(offset, val, true);
				}
			} else {
				for (var i = 0; i < bytes.length; i++, offset += 2) {
					var s = Math.max(-1, Math.min(1, bytes[i]));
					data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true);
				}
			}

			return new Blob([data], {
				type: 'audio/wav'
			});
		}
	};
	//开始录音
	this.start = function() {
		audioInput.connect(recorder);
		recorder.connect(context.destination);
	}

	//停止
	this.stop = function() {
		recorder.disconnect();
	}

	//获取音频文件
	this.getBlob = function() {
		this.stop();
		return audioData.encodeWAV();
	}

	//回放
	this.play = function(audio) {
		var blob = this.getBlob();
		// saveAs(blob, "F:/3.wav");
		audio.src = window.URL.createObjectURL(this.getBlob());
	}

	//上传
	this.upload = function() {
		return this.getBlob()
	}

	//音频采集
	recorder.onaudioprocess = function(e) {
		audioData.input(e.inputBuffer.getChannelData(0));
		//record(e.inputBuffer.getChannelData(0));
	}
}